I've been thinking about using either 14 or 17 gauge aluminum electric fence wire to make an 80m horizontal loop, but I was curious how well the wire would handle power above 100 watts. At this point I'll almost certainly use the 14 gauge wire, if for nothing else because of the mechanical strength of the wire.

I can't imagine there would be any problem running 100 watts through it, but I'm curious if I'd have any issues using my AL-80B with it?

At 3MHz the skin effect makes the RF resistance of #14 copper wire about 10 times its DC value, so for the same heating effect the current rating would need to drop by a factor 3.2 to 4.7A; then you need to consider the extra resistivity of aluminium compared to copper.

Actually is it rated at 17 amps but it is used with 15 amp circuits. It is also rated at about 20 amps in a cable and about 32 amps single wire open air. When you consider aluminum wire vs copper you general size up two wire sizes over copper for same circuit. So figure on about 20 amps max for 14ga aluminum single wire open air.

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--------------------------------------Ham since 1969.... Old School 20wpm REAL Extra Class..

Actually is it rated at 17 amps but it is used with 15 amp circuits. It is also rated at about 20 amps in a cable and about 32 amps single wire open air. When you consider aluminum wire vs copper you general size up two wire sizes over copper for same circuit. So figure on about 20 amps max for 14ga aluminum single wire open air.

It will work just fine...go for it...but if you can afford a larger gauge you would be better off! Many blue moons ago I had a 300-foot longwire made of #8 gauge solid aluminum. It did the job for me running 1 kilowatt. I just bought some LMR 400 that has a solid center conductor made of copper clad aluminum. In order to keep the cost of wire to a minimum I'm seeing more and more coax and antenna material made of aluminum. I remember years ago when electricians were using aluminum wire in new home construction...they had problems with this down the road when the connections would oxidize and cause house fires.

I'm not a big fan of either aluminum (for more than one reason) or horizontal loops (which radiate straight up). But I cannot imagine that running the full legal limit will cause such antenna to melt and fall out of the sky. :-)

Either wire will work fine in the real world if you operate legally power wise. That said, I think it would be "Penny wise and pound foolish" to try to save acouple of dollars on the wire and use 17. "Man up to the bar" and buy at least 14 ga. or a little larger. (Personally, I would look hard at #12 or maybe even #10if I was using Aluminum wire. )

If you are going to all the trouble to put up a fairly large antenna, do it right. I promise you: the small wire will break at the WORST possible time ! There is a very accurate Murphy's law corollary that applies to ham radio: "An antenna will fail when it is either: very cold, loaded with ice, in a wind driven rain or you badly need for it to NOT break and don't have time to immediately fix it." The Inverse is that: "An antenna will almost never fail on a beautiful, sunny, pleasant, 75 degree day."

Biggest problem with AL wire is mechanical issues, but it is not a deal killer by any means. Just DON'T connect copper direct to the AL wire.

In a previous post a poster said a 80 meter horizontal loop radiates straight up. I suggest he read an article in QST of November 1985 titled "The loop skywire" by Dave Fischer. The computer models say it radiates straight up but in actual practice that isn't so. The actual results differ. I've used that loop for years and found it works as well as other wire antennas for dx as well is local contacts. Dave has excellent credentials and knows that actual results do not reflect what the computer model tells you.

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